Cylinder 3 misfire. Diagnosis steps

Hello fellow 1st gens. I have a 2000 Toyota Tacoma SR5 4 cylinder 2.7L and have had misfires on my 3 cylinder code P0303. I have replaced the spark plug and coil yet I’ve continued to get a check engine light after clearing the code with OBD. I was curious what my next steps might be. My local Napa Technician suggests looking at the pucks on my valves and seeing if it needs to be adjusted or replaced. Could a deep cleaning of the valve cover also be the issue or could it be lack of compression. I’m about to run a compression test to narrow down the results, but would appreciate any feedback. Thank you

 

A quick leakdown test yet?

 

I know you said you already got a new coil, but just a quick check you could swap #3 coil with another cylinder, clear the code, and see if the misfire follows cylinders. If it stays in 3 I'd check the injector for #3 cylinder next.

 

I second that. Could be looking at a valve/head issue.

 

I'd consider compression and leak down, but before buying any tools simply swap the injector first. Also if you have a pen light, take a look into the cylinder.

Does the spark plug show any moisture? burning? etc.

 

Yes. I swapped coils still misfired. Compression test resulted in 85 PSI which is low. Should be around 120 I believe. Checking the valves when I have time this weekend for leakage, valve alignment, etc. Also no damage to the spark plug as far as signs of burning or moisture.